The benefits of high-intensity interval (HIIT) sessions are well supported in the scientific literature. The great thing about these types of workouts is you get a lot of bang for your buck. Minimal time doing cardio = maximal gains. The exercise though, has to be high-intensity, meaning you can't carry on a conversation while doing it! Not only will you improve aerobic fitness, VO2 max, and work capacity it also increases testosterone levels. Steady state cardio (long duration like marathon running) can actually decrease hormonal levels including testosterone. A study found that an 8-week HIIT program using men and women increased VO2 max more following the HIIT program (15%) than in a continuous training program (9%). HIIT workouts also increase post-exercise oxygen consumption, fat oxidation, and metabolic rate. Essentially, they keep the body burning fuel long after your workout is over. Some consider this the "after burn" which according to research can last longer than 24 hours if the intensity is very high. THE GOAL Add in two high-intensity interval training sessions over the next two weeks. Following that, increase that number to three sessions a week, with a day off in between. This high-intensity interval training session includes 30-seconds of high intensity aerobic work followed by 1.5 minutes of rest or recovery, repeated for 7 rounds. This is a total of 20-minutes in the saddle including warm-up/cool-down. Eventually, try to incorporate HIIT workouts three times per week on nonconsecutive days for a week or two when you need a change from steady state cardio. WORKOUT During the bike ride, use 4-minutes to warm-up. Following that, perform 45-seconds of all out work (increase watts and rpm) followed by 90-seconds easy pedaling. Perform this 1:2 work-to-rest ratio for 7 rounds or 16-minutes not including warm-up. After your last interval, ride easy for 3-minutes to cool-down, DETERMINE YOUR CARDIO FITNESS LEVEL This is done by taking a heart rate after your last (7th) 30-second interval. Then take it again one-minute later. If you are 30/40/50+ beats lower than your max heart rate, your heart health is considered very good. If it, however, recovers only 20 beats or less ...keep up with regular cardio. **Wear a heart rate monitor if you have one or monitor it on your Apple watch or other technology. Stay Strong Together, MICHAEL WOOD, CSCS Jefit